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Here's something that appeared in another audio magazine that I believe would also be the editorial position of Stereophile.

"As in all things audio, listeners should let their ears, not the laws of physics, be their guide."

Given the laws of physics can sometimes produce both right and wrong solutions in equal proportions (vented vs. sealed speaker enclosures for example or large vs. small driver diaphrams), how much do you agree with the statement?

On a scale of 1-10 with 1 being "not at all" and 10 being totally agree, please give your answer.

Or, if you wish to state you feel this is not the policy of Stereophile, enter that position separately.

Quote:Here's something that appeared in another audio magazine that I believe would also be the editorial position of Stereophile.

"As in all things audio, listeners should let their ears, not the laws of physics, be their guide."

Given the laws of physics can sometimes produce both right and wrong solutions in equal proportions (vented vs. sealed speaker enclosures for example or large vs. small driver diaphrams), how much do you agree with the statement?

On a scale of 1-10 with 1 being "not at all" and 10 being totally agree, please give your answer.

Or, if you wish to state you feel this is not the policy of Stereophile, enter that position separately.

Quote:Here's something that appeared in another audio magazine that I believe would also be the editorial position of Stereophile.

"As in all things audio, listeners should let their ears, not the laws of physics, be their guide."

Given the laws of physics can sometimes produce both right and wrong solutions in equal proportions (vented vs. sealed speaker enclosures for example or large vs. small driver diaphrams), how much do you agree with the statement?

On a scale of 1-10 with 1 being "not at all" and 10 being totally agree, please give your answer.

Or, if you wish to state you feel this is not the policy of Stereophile, enter that position separately.

Hi, Jan.

Being that, in addition to the laws of physics being able to provide right or wrong solutions in equal proportions, I will give human senses/hearts the same creedence and say 5.

I know many a man who told me, "This girl is the greatest thing, ever," with certainty, only to be proven wrong!

(By the way, I like to think "the laws of physics" are 100% wrong in both your example of speaker enclosures - neither sealed nor vented - open baffle/dipole is the way to go, baby!)

Quote:Because I understand my ears far more than I understand the laws of physics, I'm going to say 8.

In that context 'understand' is a peculiar usage. You may, as I do, rely upon your ears as the final judge of what you do or don't like hearing, but that's not 'understanding' as such. Lets face it though, none of us can (as yet!) have new ears transplanted if our own prove to be less than accurate devices. It's the use of accurate here that I suggest is worth thinking about. As to the mark out of 10 for the original poster's question I'm not voting as the statement itself is far too simplistic to describe the complexities, and individual's differing sensitivities, to music reproduction .

Quote:And it is a lot easier to listen to something rather than try to understand all the science behind it.

Yes, and it would be a hell of a lot different, and far, far, more difficult for audio designers to achieve what they have if they didn't use science as a tool.

Quote:At the end of the day, I'm listening to the equipment - not running tests on it.

Me too but I have the feeling many who are utterly obsessed with test results as the be all and end all of audio gear evaluation aren't in the least interested in music as such.

First, you're making this too complicated. Clearly I did not mean that I can build an artificial ear. I can't even name the parts that make up the ear.

What I meant was, I can look at charts and graphs all day, but they will not tell me what I'll hear. Maybe some people can do that - I cannot, because I don't understand them in such a way that I can use charts to tell me what something will sound like. In addition, I have no need to get to know them that well, because I can hear what I think sounds good. This hobby already takes up enough of my time without reading physics textbooks.

Second, of course people who create audio equipment would have a hard time doing it without the science. But they'd also have a difficult time if they couldn't hear what was going on (and don't give me the ridiculous hypothetical that an old master musician goes deaf and can still make audio equipment - he used to be able to hear). Anyhow, this statement just addresses the conflict.

Quote: Me too but I have the feeling many who are utterly obsessed with test results as the be all and end all of audio gear evaluation aren't in the least interested in music as such.

Quote:What I meant was, I can look at charts and graphs all day, but they will not tell me what I'll hear. Maybe some people can do that - I cannot, because I don't understand them in such a way that I can use charts to tell me what something will sound like. In addition, I have no need to get to know them that well, because I can hear what I think sounds good. This hobby already takes up enough of my time without reading physics textbooks.

Yes, I agree with all that but I'd like to argue with your usage of 'hobby' . I'll refrain however for fear of upsetting Lamont.

Quote:Second, of course people who create audio equipment would have a hard time doing it without the science. But they'd also have a difficult time if they couldn't hear

Yes & so? ...

Quote: (and don't give me the ridiculous hypothetical that an old master musician goes deaf and can still make audio equipment - he used to be able to hear).

Laws of "physics", or any other branch of science or fields one wishes to call "it", are deduced descriptions of how things work, and everything is bound by "it", even your ears.

Sealed or vented speakers all follow the same laws. Though the results may sound different, it's all explainable by those laws.

I would still let my ears be my guide, with caveats. If the manufacturer makes claims that the device operates on principles that violate the laws of physics, then that's a deal killer regardless of what my ears tell me (hearing can be fooled).

Quote:the laws of physics can sometimes produce both right and wrong solutions

LOL, I have no idea about Stereophile's position, but only among audiophiles will you see claims that the laws of physics can be wrong!

Loudspeaker design is a compromise based on weighing various evils / goods against others. If there were one best way to make loudspeakers, they'd all be made that way and vendors doing otherwise would soon be out of business.

Quote:the laws of physics can sometimes produce both right and wrong solutions

LOL, I have no idea about Stereophile's position, but only among audiophiles will you see claims that the laws of physics can be wrong!

Loudspeaker design is a compromise based on weighing various evils / goods against others. If there were one best way to make loudspeakers, they'd all be made that way and vendors doing otherwise would soon be out of business.

--Ethan

___________________Bring back DUP

Ethan. He didn't claim the laws of physics to be wrong. He said, the laws of physics could produce both right and wrong solutions. Like a 20 foot high rebar reinforced concrete dike or a 20 food high dyke made of colofull paper. One works, one not, both used the rules of physics.

Quote:Like a 20 foot high rebar reinforced concrete dike or a 20 food high dyke made of colofull paper. One works, one not, both used the rules of physics.

No, the designer who made a dyke from colored paper did not use the laws of physics. Or at least not properly. And don't tell me that audiophiles don't dismiss physics and other hard realities - I see it here every day. Just look at this thread:

Quote:Here's something that appeared in another audio magazine that I believe would also be the editorial position of Stereophile.

"As in all things audio, listeners should let their ears, not the laws of physics, be their guide."

Given the laws of physics can sometimes produce both right and wrong solutions in equal proportions (vented vs. sealed speaker enclosures for example or large vs. small driver diaphrams), how much do you agree with the statement?

On a scale of 1-10 with 1 being "not at all" and 10 being totally agree, please give your answer.

Or, if you wish to state you feel this is not the policy of Stereophile, enter that position separately.

Hi Jan,

I would have to place listening as the final criteria, although the specs have to be excellent to begin with. Otherwise, one might compensate the flaws of one component with another. As a simple example, if an amplifier is -1db at 20khz, the preamplifier would have to be +1db at 20khz to compensate. However, this creates other problems. Because of such my answer would be a 9 for listening.

After that listening is the final criteria as measurements just does not measure everything. As an example, let's consider a distortion analyzer pictured below.

As anyone who has ever worked with a physical distortion analyzer, it does measure -110db or so, but is not discriminating enough to show 0.01db, 0.1db, 0.3db or maybe even 0.5db differences, even if measuring only 20db down. A computer based program might. An oscilloscope also lacks resolution.

Even then we have the problem in that capacitors are in the analyzer's circuitry which would mask any information as DA effects are present in the circuitry's capacitor. This problem includes software types used in computers. And computer based problems also has some "averaging" characteristics according to the manufacturer I spoke to, again affecting the accuracy.

Another interesting observation is that although the distortion analyzer will not measure DA, a simple voltmeter easily measures it, especially electrolytic capacitors. DA is also quite well known in the RF field. So how can it influence both above and below the audio band while mysteriously bypassing and not affecting the audio band, the music?

In the final analysis, it appears that listening is the only true final determiner of the sound quality at this present time.

I don't wish to get this thread too far off course, but I have to ask.

Quote: Hi Jan,I would have to place listening as the final criteria, although the specs have to be excellent to begin with.

As an active designer/engineer, what is your criteria for "excellence" in specs? We've been told by Winer that there are only three (or four) specs Winer looks at but never given any further explanation of that concept.

I've listened extensively to single ended triodes operating a single driver, full range system installed in an open baffle. With the addition of an open baffle woofer this was what I consider to be a very musically involving system that had few real faults though the specs would not lead most people to believe it so.

I've also listened to fullrange, multiple driver, ported systems with death defying impedance swings combined with hair raising phase angles being driven by 500 watt, immeasurable THD spec'd, solid state behemoths that I walked away from without so much as a second thought.

Given the wide diversity in components available today, please explain a bit more about how you decide when specs are "excellent".

If you were designing/assembling a piece of gear, and found some aspect with TERRIBLE measured values, at what point would you not even proceed to listening? Or, is there such a point?

Thanks Buddha and Jan. Tough questions. I cannot speak for anyone else, but when I design, it depends upon which spec and other parameters. I know that sounds like a cop out, but I can give a couple of examples to show how complex the decision making is.

As one example, I try to obtain the widest frequency response possible, yet keep the number of parts and stages to a minimum. Why use two stages and the extra parts when one can be designed to work just as well.

With the preamplifiers I try to obtain the lowest possible distortion, yet try to use the least amount of feedback possible. Getting a tube preamplifier to -80db typical without global feedback is quite a challenge. Don't know if it needs to be that low, but it does not hurt. One could use differential stage, but there are many more parts to degrade the sound.

With amplifiers, I prefer tube types but acknowledge that distortion will not be as low as solid state. However, I obtain as low as possible harmonic distortion. There are pluses that solid state cannot equal.

I hope my reply does not come across as a cop out or commercial. Not meant to be, but alot of thought goes into my designs. My goal is to have a component that is totally clear and transparent. Then work on getting the source, speakers, ICs, etc for the most natural, emotional, accurate sound possible.

Take care and ice storm coming in a few hours.

ps. As a quick add on, how it possible that a 6sn7 preamplifier and E88cc preamplifier can measure the same frequency response from 20 to 20khz under sinusoidal conditions, both 0.1% or less distortion, no hum from the speakers, yet sound totally different when music is played?

Quote:Why use two stages and the extra parts when one can be designed to work just as well.

"Just as well" would also seem to be a "floating" reference that only you can reach by considering all of your options and all of your priorities.

I can think of two reasons off the top of my head.

1) Both stages can be run more conservatively and therefore stay more within the limits of their operating range.

2) If the second stage maintains a constant impedance - either in or out - or polarity then that could have significant advantages to the overall performance of the product in a real world listening situation.

Nope. There are four major categories, and the others fall under those. For example, phase shift, wow, flutter, and jitter all fall under time-based errors. (This is the category I usually omit when discussing amps and preamps.) And many types of noises all fall under the Noise category. And so forth.

Quote:"Just as well" would also seem to be a "floating" reference that only you can reach by considering all of your options and all of your priorities.

I don't think so, except in special cases like high capacitance, over 150-200pf and higher in the IC. Otherwise, no loss of high frequency response. From my webpage "My Engineering and Design Philosophies"

Quote: Let's check for any high frequency response advantages. If one uses a high capacitance interconnect cable (IC), say 250pf of capacitance, and the output impedance changes from 2000 ohms to 100 ohms, the frequency response changes approx 0,4db at 100,000 cycles per second.

Using a 50pf interconnect cable results in less than 0,02db change at 100khz.

Quote:I can think of two reasons off the top of my head.

1) Both stages can be run more conservatively and therefore stay more within the limits of their operating range.

Interesting thought Jan, and I think I see where you are coming from. Luckily that does not become an issue as the output impedance (Z) of the stage is pretty constant whether the tube is run at 40% of max or 90% of Max. I would say definite yes at 20% however. The ouput Z gradually changes. The issue does come into play with solid state though, as the output Z is relatively high to quite high.

Quote:2) If the second stage maintains a constant impedance - either in or out - or polarity then that could have significant advantages to the overall performance of the product in a real world listening situation.

With a single stage, the impedance remains pretty study. Polarity is generally not an issue because the 2nd stage is usually a cathode/source/emitter follower and does not invert the signal. However, there are a few other designs, such as a Mu follower that does invert, but that design still uses more parts.

Adding a second stage adds parts, distortion, and adds frequency dependent feedback from stage to stage through the power supply. I have an article explaining this in general terms.http://www.sasaudiolabs.com/theory8a.htm

I think what is all important is how transparent and uncolored (adding any form of distortion from the input signal) the product is? How true to the music is the product. Unfortunatly most tubes won't work as a single stage preamplifier. Fortunately, some do and can produce a truly "uncolored" accurate musical reproduction. Reliability is also improved as the chance of breakdown is minimized.

If I was test driving an unfamiliar car, I could render a pretty good "seat of the pants" evaluation to the steering feedback, braking response, and a hundred other little things. But most cars (especially high performance ones) start out as laboratory creatures. There's a lot of hard physics in a well designed automobile.

No matter what my final driving assessment, I would want to see hard numbers, derived by a competent tester. Only then would I be satisfied that the car performs well beyond the boundaries of any "wild edge" that I would subject it to.

It's the same in audio. The laws of physics prevail in sound reproduction to a very great extent, so why not quantify and verify their application?

I'll vote with a "4" to the premise that your ears should be your guide. To give absolute endorsement to an audio product (especially by a reviewer) judged strictly on how he/she thinks it sounds is totally irresponsible. Maybe I hear things differently.

And as far as those "exquisite, infallible instruments" (your ears) are concerned, consider the fact that two very gifted listeners can arrive at totally opposite poles regarding sound quality. Maybe one of those instruments is miscalibrated.

I just think that measurements make the picture complete (thank you, JA!) and that any audio journal that dismisses their importance is simply in denial.

Actually I'm going to lean toward the positive on this one -Jan has hit upon something here. .

I'll throw it a 7 and here's why.

From systems' development perspective it begins with the maths - and no amount of maths can produce anything that "sounds good".

As the years rolled around when I first graduated in 1984, picking up experience as one does in an industry, it became clear very early on that the science/maths and modelling only get you to within 30 clicks of where you want to be - not the full journey.

This is good for setting a course for the journey. But the completion of the journey is done with trial, error, itterative research and development and hearing as the REAL test equipment.

Plenty of times have I been in situations with a development team, when the maths+test equipment go against the ears. But we have found the guilty influence in the end - and often adopted it as a way forward.

Caveat: Huge gulf between acoustics and Psycho acoustics - if the ears can measure it - so can the test equipment. The human being is not consistent - I find myself having to work a problem over a long time because too many human factors exist - all cause listening problems.

Try this as an experiment - do a listenning test at the coldest you can make your house - then do exactly the same test at its hottest. Very simple stuff. If you had my Bruel and Kjaer Microphones there along with my Racal spectrum analyser - you can measure the differences as well.

This is one of the reasons why this subject is so special - But what I cannot subscribe to are the obvious myths and fairy tales that some of the magazines try to disguise as science. Thats why I cant give this a full 10 because it must come packed with empirical evidence.

Quote: Caveat:... if the ears can measure it - so can the test equipment.

I have to respectably disagree with the above comment. For example, consider two polyprop capacitors. Both have the same ESR and DA measurements according to the specs, less than .02% in both cases. Both can easily be tested and both measure the same, whether oscilloscope or other measuring device, when presented with a sine wave.

However, one capacitor has considerably thicker metalized material than the other, so the difference in internal resistance, although slight, is present. In fact the measuring devices themselves contain capacitors. So how can we measure capacitors if the internal capacitors in the measuring devices themselves are causing resolution problems/insensitivities?

I believe this can easily proven in that a spectrum analyzer can "measure to -130db", yet cannot measure the DA of the best capacitors which are only -70 to -80db down. In fact an analyzer should easily measure the DA of an electrolytic which is only approximately -34 to -40db down, yet cannot. Yet a simple FET voltmeter can measure it, although with little resolution.

Sorry but I have to respectably disagree with the assumption that typical audio measuring equipment measures everything, or can measure what the ear can.

Quote:A sound engineers epithet..."If it can be heard - it can be measured" ... it's a simple piece of logic.

Too simple IMO.

I can't find the exact quote right now, but it came from an engineer/designer at H.H. Scott when they were a well regarded line (which goes back more than just a few years) and went more or less like this, "If it sounds good and meaures good, it is good. If it sounds bad and measures good, you measured the wrong thing."

The quote of the epithet in that earlier post isnt mine - It's Jon Hobden's - Acoustical and Physical Sciences expert to the Aerospace industry -(De-constructing cabin noise in civil Airliners) and I believe that to a be a golden piece of pure logic. Simple is beautiful

As I said in my original post - that you can be doing tests where the results or what your looking at doesnt match what you'd expect or what you may be experiencing at the time. As a direct example - I have had occasion when an amplifier was manifesting cross-over distortion at the 2nd stage bias chain. What I considered to be enough to be audible. Yet it wasnt. The amplifier was packing out full output without any audible distortions at all.

What should I do at that point? Change the conditions of the test, to seek out and find what is causing such an odd occurance -- or say the fairies have come to town?

Here was a differential - my eyes and test equipment had one value -- my ears had the other. One just needs to find out why.

No...I want to know why...So I changed the conditions of the test- to find that the output stage was compensating for the errors in the bias chains cancelling out the error due to capacitive properties in the power transistors and driver circuit. I eventually, after enough searching, obtained the empirical evidence I needed. With the right test - the right conditions - enough time, one can track down the facts.

If you guys are saying that if you have the human experience of hearing something -- and it "cannot" be measured... We're back in the land of the Fairies.

Quote:If you guys are saying that if you have the human experience of hearing something -- and it "cannot" be measured... We're back in the land of the Fairies.

That would seem to be a bit of a stretch. What we can measure and what we know to measure today is far different than what we could or knew to measure forty years ago, even twenty years ago. On occasion those fairies leave some knowledge under our pillows.